Fluid-pressure-controlling apparatus



Dec. 28', 1926.

A. THOMPSON FLUID PRESSURE CONTROLLING APPARATUS 2 Sheets-Sheet 1 Filed May 4, 1925 INVENTOR BY R. M 4. ATTORNEY H. A. THOMPSON FLUID PRESSURE CONTROLLING APPARATUS Filed May 4. 1925 2 Shee ts-Sheet 2 lNVENTOR BY Q-pz- W Ahi ATTORNEY Patented Dec. 28, 1926.

UNITED STATES 1,611,961 PATENT OFFICE.

HOWARD A. THOMPSON, F WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH 8c SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORA- TION OF PENNSYLVANIA.

FLUIlJ-PBESSURE-GONIROLLING APPARATUS.

Application filed May 4, 1925. Serial No. 27,988.

' Myv invention-relates to fluid pressure controlling apparatus, and has for an object the provision of means for varying the pressure supplied to a fluid pressure responslve 6 device in response to variations in the energization' of an 'electro-responsive device.

I will-describe several forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a view showing one form of fluid pressure controlling apparatus embodying my invention and applied to a railway car retarder.

Figs. 2 and 3 are views showing modificalar parts in each of the views.

Referring first to Fig. 1, the reference characters 1 and 1 designate the track rails of a railroad which rails are provided with a car retarder designated by the reference character B. This retarder in the form here shown comprises two braking bars 2 and 2*. associated with the track rails 1- and 1, respectively, and adapted when forced outwardly to engage the inner faces of the wheels of a car moving along the railroad track. These braking bars "are controlled by a longitudinal rod 7 carrying wedges 3 which co-act with links 4 attached to the braking bars 2 and 2 The operation is such that when the rod 7 is shifted to the left the braking bars 2 and 2 are free to move inwardly away from the track rails 1 and 1*.

whereas when the rod 7 is shifted to the right these braking bars are forced outwardly toward the track-rails to reduce the speed of a car passing thfiough the retarder. The rod 7 is controlled by a fluid pressure responsive device, which, as here shown, is a motor M comprising a cylinder 6 and a piston 5. Fluid pressure is supplied to the left-hand end of cylinder 6 by a pipe 9 to shift the piston 5 and the rod 7 to the right, thereby moving the bars 2 and 2 into braking positions.

The supply of fluid pressure to the pipe 5) is controlled by a valve device V embodylng my invention. In the form shown 1n Fig. 1 this valve device comprises a chamber 43, one wall of which is movable. As here shown, the movable wall is in theform of a diaphragm 40. The supply of fluid pressure to the chamber 43 from the pipe 13 is controlled by an inlet valve 41, whereas the exhaust of fluid pressure from the chamber 43 through a pipe 14 to atmosphere is controlled by an exhaust valve 42. These valves are connected with the diaphragm 40 and are so arranged that when the diaphragm is not influenced by external force the inlet valve 41 is closed and the exhaust 42 is open; whereas, when the diaphragm 40 is moved inwardly by an external force the inlet valve 41 opens and the exhaust valve 42 closes. Pipe 9 is connected with chamber 43.

The reference character E designates an electro-responsive device for exerting a variable pressure on the diaphragm 40 in opposition to the pressure exerted on this diaphragm by the fluid pressure in chamber 43. As here shown, the electro-responsive device E comprises a solenoid 39 containing a plunger 8. The solenoid 39 is provided with a circuit comprising means for varying the strength of the current supplied to the solenoid. In the form here shown, this circuit includes a battery 10, a resistance 11, and a manually operable contact 12 co-act ing with the resistance 11. As the contact 12 is swung to the right, the portion'of the resistance 11 which is included in the circuit for the solenoid 39 is decreased so that the amount of current flowing in this solenoid is increased. As contact 12 is swung to the left, the portionof the resistance 11 which is included in the circuit of solenoid 13 is increased so that the amount of current flowing in the solenoid is decreased.

The plunger 8 acts directly on the diaphragm 40, and so exerts'a variable pressure thereon depending on the amount of current which is supplied to the solenoid 39. As the pressure exerted by plunger 8 is reduced, the inlet valve 41 moves towards its closed position and the exhaust valve 42 moves towards its open position thereby reducing the presf the change occurs in the current supplied to the solenoid 39. As the pressure exerted by the plunger 8 increases, the opening of intake valve 41 increases and the opening of exhaust valve 42 decreases, thereby increasin the pressure in chamber 43 until a balanced condition is reached, whereupon the movement of the diaphragm ceases. It will be seen, therefore, that the pressure supplied to the motor M varies in accordance with Iposition of the movable contact 12, and so t ing through the retarder R is determined by the position of the contact 12. 7

Referring now to Fig. 2 in the valve device which is here designated V, the movable wall of the chamber43 is a piston 15 sliding in a cylinder 15; The plunger 8 of the electro-responsive device E acts directl on the piston 15.. The inlet valve 41 an the exhaust valve 42 are controlled by anarm 17 which is pivotally connected at an intermediate point with a tongue 16 projecting slownwardly from the piston 15. The intake valve 41 is biased to its closed position by a SpI'Hlg 18, and the exhaust valve 42 is biased to the open position by aspring 19. When the pressure exerted by plunger 8 is zero, the piston 15 will be at the uppe 11m1t of its stroke-in which position the intake valve 41 that the is closed and the exhaust valve 42 is open,-s o

ressure in chamber 43 is atmospheric. hen a downwardpressure is exerted on piston 15 by the plunger 8, the first result is to cause arm 17 to swing in counterclockwise direction, thereby closing theexi "haust valve 42, and after this occurs the further downward movement of piston 15 causes the arm 17 to swin in clockwise direction around its left han end as a ,cen-

er, thereby opening the intake valve 41.

en the pressure inchamber 43 reaches a certain value, .it will over-balance the pressure exerted on the piston 15' by afiplunger 8 ,whereupon this vpiston will rise su ciently to permit valve .41 to close and the pressure in chamber 43 will then remain constant. Anincrease in the pressure exerted on piston 15 byg'plunger 8 will result in opening the intake valve 41 untila: given inerease'of the pressure in chamber 43" has occured,

- whereupon the valve, 41 will again close.

" vice E.

A' decrease in the pressure exerted on piston 15 by plunger 8 will result in upward movement ofv the piston and this will permit the exhaust valve 42 to open until the a given value, whereupon the piston 15 will move downwardly tocause valve 42 to close and the conditions will again remain constant .until a further change occurs in the energization of the electro-responsive dee braking eifort exerted on a car pass- Referring now to 3, the valve device which is here designated V is similar to the exhaust port 14 being located in the cylinder- Wall 15 above the piston. The lower end of the exhaust valve 42 co-acts with the stem ofthe intake valve 41, so that as the piston'moves downwardly the exhaust valve is closed and the intake valve is opened against the action of spring 18 to admit fluid pressure to the chamber 43. -When the pressure in this chamber becomes of such value as to slightly overbalance the downward force on piston 15, this piston moves up far enough to allow the intake valve 41 to close. If now the downward pressure on piston 15 is reduced, this piston will move upwardly due to the fluid pressure in chamber 43, and so will cause the stem of the exhaust valve 42 to engage a projection 20 located in the cylinder above chamber 43 to such value that thepistonagain moves downwardly far enough to permit the exhaust valve to close.

plied tot e solenoid 39 the pressure in chamber 43, and so in the pipe 9, may be varied.

Referring to Fig. 4, the valve device which is here designated shown in Fig. 1, except that a floating lever 44, corresponding to.the floating lever 17 in Fi 2, is used to control the valves 41 and .42. he lever 44'is provided with a central upwardly projecting tongue 44 which engages the iaphragm 40, The electromagnetic device w ich is here designated E is member 21 co-acting with an armature 38. This armature is operatively connected with the diaphragm 40 through themedium of a rod 45. In Fig. 4, instead of directly controlling the supply of fluid pressure to the electro responsive device by the Valve device V, I

I It follows i that by va'rg'ing the amount of current supis similar to that of the Z-armature type, comprising a field a valve 49 co-actingwith the seat -"23.- The valve 49 is attached to a stem 50 which car- 'ries a piston 51, and this stem aligns with a stem 50 which carries two other pistons 52 and 48. The upper face of the piston 48 I is exposed to the fluid ressure in chamber 43 I through a pipe 46, an

the lower face of this Plston 1s 'e pp d to a o phere by virtu'eof structure, when the pressure above the piston 48 is increased, the valve 49 moves downexhaust port 24. The space between pistons 51 and 52 is'exposed to the pressure in pipe 9 through a passage 25. With this wardly until the pressure exerted on the underside of piston 52, that is, the pressurein pipe 9, becomes suflicient to move pistons 48 and 52 upwardly. The pressure on the under side of piston 51 then closes the valve 49 and so the increase of pressure in pipe 9 stops. When .the pressure above piston 48-decreases, this piston and piston 52 rise, thereby opening pipe 9 to atmosphere through ports 25, 25 and 24, and so the pressure in pipe 9 is reduced to such value that pistons 48 and52 drop to again close the port 25. Due to the comparatively small area of piston 52 and the comparatively large area of piston 48, it will be seen that a relatively small controlling pressure in chamber 43 will serve to govern a relatively large pressure in pipe 9. In other words, a comparatively small current in solenoid 39 will control comparatively large pressures in pipe 9, and so in the fluid pressure responsive device.

Although I have herein shown and described only four forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: i

1. In combination, a fluid pressure chamber, a source of fluid pressure, an inlet valve between said source and said chamber, an exhaust valve between said chamber and atmosphere, said chamber having a movable wall controlling said valves in such manner that as the wall moves in response to pres-' sure in said chamber the inlet valve closes and the exhaust valve opens, whereas when the wall moves in the other direction the inlet valve opens and the exhaust valve closes, and electromagnetic means i for exerting variable pressure on said wallin opposition to the fluid pressure in said chamber.

2. In combination, a fluid pressure chamber, a source of fluid pressure, an inlet valve between said source and said chamber, an

exhaust valve between said chamber and atmosphere, said chamber having a movable wall controlling said valves in such man! ner thatas the wall moves in response to pressure in said chamber the inlet valve closes and the exhaust valve opens, whereas when the wall moves in the other direc-' tionthe inlet valve opens and the exhaust valve closes, an electromagnetic device for exerting pressure on said wall in opposition to the pressure exerted thereon by fluid in her, an' electromagnetic device, means manner that as the wall moves in response to pressure in said chamber the inlet valve closes and the exhaust valve opens, whereas when the wall moves in the other direction the inlet valve opens and the exhaust valve closes, electromagnetic .means for exerting variable pressure on said wall in opposition to the pressure exerted thereon by fluid in said chamber, and a pressure regulating valve responsive to variations of pressure in said chamber.

4. In combination, a fluid pressure chamvarying the strength of current supplied to said device, means controlled by said device for varying the fluid pressure in said chamber, and a pressure regulating valve responsive to variations of the pressure in said chamber.

5. In combination, a fluid pressure chainfor ber, a source of fluid pressure, an inlet valve between said source and said chamber, an exhaust valve between said chamber and atmosphere, a floating lever acting on said valves, said chamber having a movable wall co-acting with said lever in such manner that as the wall moves in responseto pressure in said chamber the inlet valve closes and the exhaust valve opens, whereas when the wall moves in the other direction the inlet valve opens and the exhaust valve closes, and electromagnetic means for exerting variable pressure on said wall in opposition to the fluid pressure. in said chamber.

6. 'In' combination, a fluid pressure chamber, a source of fluid pressure, an inlet valve L between said source and said chamber, an exhaust valve between said chamber and atmosphere, a member biased in one direction by the pressure in said chamber and arranged to open the exhaust valve and close the inlet valve when the member moves in response to such bias and to close the exhaust valve and open the inlet valve when the member is moved in'opposition to the pressure in said chamber, an electromagnet for exerting pressure on said member in opposition to the pressure in said chamber, and means for varying the energizationof said electromagnet. 4

t In testimony whereof affix my signaure.

HOWARD A. THOMPSON. 

